Golf club head with textured striking face

ABSTRACT

A golf club head includes a heel portion, a toe portion, a hosel, and a striking face. The striking face includes a plurality of scorelines each having an average depth no less than about 0.10 mm, a plurality of micro-grooves each having an average depth no greater than about 0.010 mm, and a plurality of textured surface treatment regions superimposed on the micro-grooves so as to at least partially intersect the micro-grooves.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit, under 35 U.S.C. §119(e), of U.S.Provisional Application No. 61/754,302; filed Jan. 18, 2013, the subjectmatter of which is incorporated herein by reference in its entirety.

BACKGROUND

This disclosure relates generally to the field of golf clubs. Moreparticularly, it relates to a golf club head with a textured strikingface for imparting greater spin to a golf ball when the golf ball isstruck.

A common goal of golf club head design, specifically for iron-type andutility-type club heads, and particularly for wedges, is to create astriking face for the club head that imparts significant spin to astruck ball. The striking face of such a club head typically has aplurality of parallel horizontal grooves or score lines. These scorelines assist in imparting spin at least by channeling water and debris,and by increasing the friction between the striking face and the surfaceof the ball. The spin-imparting qualities provided by such score linesare limited, however, by United States Golf Association (“USGA” herein)regulations governing score line geometry (and similar regulations ofother international golf equipment regulatory bodies). Moreover,conventional score lines fail to account for low-scale dynamicinteractions between the striking face and the ball.

Further improvements in the spin-imparting characteristics of club headstriking faces have included the provision of low-scale surface texturesin addition to, or in place of, the conventional score lines. Suchsurface textures, however, tend not to take into account the specificinteraction between a conventional elastomer-covered golf ball and ametallic striking face. Moreover, conventional surface texturing issubject to rapid wear, is often costly to produce, and may detract fromthe aesthetic quality of the club head. Furthermore, conventionalstriking face textures are generally ineffective at providing a highdegree of spin for each of the multitude of different types of golfshots that a golfer may attempt. For example, a ball hit with a clubhaving a conventional club head that is swung at a specific speed wouldhave different degrees of spin depending on whether the ball is squarelyaddressed by the club face or hit with an open club face. Otherconditions, such as moisture on the club face and/or the ball, andwhether the ball is struck with a full swing, half swing, or chip-typeswing of the club, can affect the degree of spin imparted to the ball.

The creation of spin, particularly back-spin, on a struck golf ball, islargely a function of the magnitude of the frictional contact or“traction” between the striking face of the club head and the ball onimpact. Where a high degree of back-spin is desired, as in higher numberirons and wedges, maximizing this traction factor is therefore a designgoal. Increased traction is generally associated with increased surfaceroughness of the striking face. Surface roughness is commonly expressedin terms of R_(a), defined as follows:R _(a)=1/nΣ _(i=1) ^(n) |y _(i)|where n is the number of sampling points and y is the deviation from amean line (at a given sampling point). As a practical matter, R_(a)represents the average of deviations from a mean line over a2-dimensional sample length of a surface.

Another surface roughness parameter is known as R_(t) (sometimesreferred to as R_(y)). This parameter represents the maximumpeak-to-trough distance in a given 2-dimensional sample length of asurface.

The regulations of the USGA limit the surface roughness of the strikingface of golf clubs generally to a degree of roughness no greater thanthat imparted by sand-blasting or fine milling. In practical terms, thisstandard has been interpreted to mean a surface having a value of R_(a)no greater than 0.0046 mm (180 μin.), and a value of R_(t) of no morethan 0.025 mm (1000 μin.). Thus, the need is evident to maximize thetraction between the club face and the struck ball without exceeding theroughness maximum established by USGA rules.

Accordingly, a textured striking face for a golf club head has beensought that imparts a high degree of spin to the ball for a wide varietyof golf shots under a wide variety of conditions, that has good wearcharacteristics, that complies with USGA rules, and that enhances (or atleast does not detract from) the aesthetic qualities of the club head.

SUMMARY

In one aspect, the subject of the disclosure is a golf club head,comprising a heel portion, a toe portion, and a striking face definedbetween the heel portion and the toe portion, wherein the striking faceincludes a grid of horizontal score lines, a first textured surfacepattern of micro-grooves intersecting the score lines, and a secondtextured surface pattern superimposed on the first textured surfacepattern between the horizontal score lines of the grid. In anotheraspect, the subject of the disclosure is a method of forming aspin-inducing textured surface on a golf club head having a heelportion, a toe portion, and a striking face between the heel portion andthe toe portion, wherein the method comprises (a) forming a grid ofhorizontal score lines on the striking face; (b) forming a firsttextured surface pattern of micro-grooves intersecting the score lines;and (c) forming a second textured surface pattern superimposed on thefirst textured surface pattern between the horizontal score lines of thegrid. In a specific embodiment, the micro-grooves of the first texturedsurface pattern are formed by mechanical milling, and second texturedsurface pattern is formed by laser etching.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a golf club head, showing atextured striking face in accordance with an embodiment of thisdisclosure;

FIG. 2 is a front elevation view of the golf club head of FIG. 1;

FIG. 3 is a toe side elevation view of the golf club head of FIG. 1;

FIG. 4 is a cross-sectional view taken along plane 4-4 of FIG. 2;

FIG. 5 is detail view of a portion of the cross-sectional view of FIG.4;

FIG. 5A is a detail view of a portion of the cross-sectional view ofFIG. 5;

FIG. 6 is detail view of a portion of the cross-sectional view of FIG. 4according to another embodiment of this disclosure;

FIG. 7 is a detail view of a portion of the cross-sectional view of FIG.4 according to another embodiment of this disclosure;

FIG. 8 is a flow chart illustrating a method of forming a texturedstriking surface on a golf club head in accordance with an embodiment ofthis disclosure;

FIGS. 9-11 are front views of a portion of a golf club head with astriking face plane corresponding to the plane of the paper, that showthe steps of forming a spin-imparting textured striking face inaccordance with an embodiment of this disclosure; and

FIG. 12 is detail view of a portion of the front view of FIG. 11.

DETAILED DESCRIPTION

The drawings and their descriptions may indicate sizes, shapes andconfigurations of the various components. Such depictions anddescriptions should not be interpreted as limiting. Alternative sizes,shapes and configurations are also contemplated as within the scope ofthis disclosure.

Referring first to FIGS. 1 through 3, a golf club head 10 of theiron-type includes a heel portion 12, a toe portion 14 opposite the heelportion 12, a front portion 72, and a rear portion 70 opposite the frontportion 72. The golf club head 10 further includes a top portion 64 anda sole (bottom) portion 58 opposite the top portion 64. The heel portion12 further includes a hosel 52 extending therefrom for associating thegolf club head 10 with a shaft (not shown). The hosel 52 defines avirtual central hosel axis 54. The front portion 72 further includes astriking face 16, defined as the planar exterior surface portion of thefront portion 72 that generally conforms to a virtual striking faceplane 56 and is adapted to contact a golf ball at a factory-designatedloft angle LA (see FIG. 3). The striking face 16 is formed with surfacefeatures that increase traction between the striking face and a struckgolf ball, for both ensuring good contact with the ball (for example, inwet conditions), and imparting a degree of spin to the ball, e.g. forstability in flight. Included in these surface features is a grid ofsubstantially parallel horizontal grooves or score lines 18. The scorelines 18 and the other surface features will be described in detailbelow.

The golf club head 10 is preferably formed of a metal, e.g. titanium,steel, stainless steel, or alloys thereof. More preferably, the mainbody of the club head 10 is formed of 431 stainless steel or 8620stainless steel. In some embodiments, the main body of the club head isintegrally or unitarily formed, while in other embodiments, the mainbody is formed of plural components that are welded together orotherwise permanently associated with each other. For example, in someembodiments, the club head 10 is formed of a main body of a firstmaterial, and a striking wall (including the striking face 16) of asecond material different from the first, and welded to the main body.

Referring to FIGS. 2 and 3, the golf club head 10 is shown in a“reference position.” As used herein, “reference position” denotes aposition of a golf club head, e.g. golf club head 10, in which the soleportion 58 of the golf club head 10 contacts a virtual ground plane 50such that the hosel axis 54 of the hosel 52 lies in a virtual verticalhosel plane 66, which intersects the virtual striking face plane 56 toform a virtual horizontal line 62.

Referring specifically to FIGS. 2 and 3, a first virtual vertical plane74 is perpendicular to the striking face plane 56 and passes through theends of the score lines 18 proximate the toe portion 14. A secondvirtual vertical plane 76 is perpendicular to the striking face plane 56and passes through the ends of the score lines 18 proximate the heelportion 12. The region of the striking face 16 toe-ward of the firstvirtual plane 74 constitutes a toe region 78 of the striking face 16.The region of the striking face 16 heel-ward of the second virtual plane76 constitutes a heel region 86 of the striking face 16. The region ofthe striking face 16 between, and delimited by, the first and secondvirtual planes 74 and 76 constitutes a central region 68.

Referring specifically to FIG. 2, the striking face 16 further comprisesa face center 80. The face center 80 is located equidistant between thefirst virtual plane 74 and the second virtual plane 76. The face center80 is also equidistant between an uppermost point 82 of the strikingface 16 and a lowermost point 84 of the striking face 16.

In alternative embodiments, the golf club head 10 is of a type otherthan an iron-type as described above. Nonetheless, the type and,relatedly, the loft angle of the golf club head 10 are preferablyselected such that the effect of any imposed surface texture describedbelow, on ball trajectory, is desirable. For example, backspinproduction is generally a more desirable feature of high-loftediron-type clubs and wedges. As the golfer nears the pin, precision ingolf shots generally becomes more critical than other considerations,such as distance. As another example of desirability, the effect oftraction between a striking face and a golf ball is understood tocategorically differ between differently-lofted club heads. Golf balls,over the duration of contact with a club head having a relatively lowloft angle, have been observed to follow a retrograde motion, i.e., theytravel upwardly, change course, and return downwardly, resulting inforward spin. Golf balls, over the duration of contact with a club headhaving a relatively high loft angle, have been observed to travel onlyupwardly, resulting in backspin. Because of these considerations, thestriking face surface textures variously described below are preferablyapplied to a club head of a loft angle no less than about 15°, morepreferably no less than about 18°, and even more preferably no less thanabout 35° (e.g. a wedge-type golf club head).

As shown in FIGS. 1 and 2, the striking face 16 includes a gridcomprising a plurality of substantially horizontal score lines 18,typically formed by mechanical milling (e.g. spin-milling).Alternatively, in some embodiments, the score lines 18 are formed bystamping, casting, or other known method. The score lines 18 typicallyhave an average width no less than 0.1 mm, more preferably between about0.25 mm and 1.0 mm, and even more preferably, substantially equal toabout 0.90 mm. For all purposes herein, score line width is to bedetermined using the “30 degree method of measurement” (as described inAppendix II of the USGA Rules of Golf, Effective Jan. 1, 2012).Additionally, or alternatively, the score lines 18 have an average depthof no less than about 0.10 mm, more preferably between about 0.25 andabout 0.60 mm, and most preferably substantially equal to about 0.51 mm.The length and number of score lines 18, and the spacing between them,are generally selected as to conform to USGA regulations. For allpurposes herein, the “depth” of a score line, e.g. score lines 18, ismeasured from the general planar surface of the striking face 16, whichthus constitutes a datum plane. Additionally, or alternatively, thescore lines 18 each have a maximum width and a maximum depth within therespective ranges of average width and average depth discussed above.

The striking face 16 is also provided with a first textured surfacepattern comprising a first plurality of very narrow, relatively shallowgrooves 20, which may be called “micro-grooves.” The first plurality ofmicro-grooves 20, which may be formed by precision mechanical milling(e.g., CNC milling), is advantageously formed as a pattern ofsubstantially parallel, arcuate lines intersecting the score lines 18.The first textured surface pattern formed by the micro-grooves 20preferably covers at least the central region 68 of the striking face,and preferably extends at least partly into the toe region 78. Morepreferably, the first textured surface pattern extends at least partlyinto the toe region 78 and the heel region 86. Preferably, the firsttextured pattern extends toward the toe portion past the uppermost point82 of the club head 10 (see FIG. 2). In some embodiments, the firsttextured pattern covers the majority, and in some cases the entirety, ofthe toe region 78 of the striking face 16. Alternatively, or inaddition, the first textured surface pattern covers the entirety of thestriking face 16 of the club head 10.

The micro-grooves 20 preferably have an average depth (measured inaccordance with depth d as shown in FIG. 5A) no greater than 0.025 mm(1000 μin.), more preferably between 0.015 mm (600 μin.) and 0.025 mm(1000 μin.), and even more preferably between 0.020 mm (800 μin.) and0.025 mm (1000 μin.). Additionally, or alternatively, the microgrooves20 preferably have an average width (measured in accordance with widthw₂ of FIG. 5A) of between (0.25 mm (0.010 in.) and 0.51 mm (0.020 in.),more preferably between 0.30 mm (0.012 in.) and 0.43 mm (0.017 in.). Thedimensions of the micro-grooves 20 and the spacing between them willhave a significant effect on the value of R_(a) of the striking face.Thus, these dimensional parameters must be selected so that the maximumpermitted value of R_(a) noted above is not exceeded. However, becauseof normal surface variation and machine tolerances, a sample pool ofclub heads having micro-grooves intended to effect a specific targetsurface roughness R_(a) value may likely effect surface roughness R_(a)values dispersed about a range. Consequently, as a practical matter, thefirst textured surface pattern is preferably selected to produce anaverage value of R_(a) close to, but still somewhat less than, thedesired optimal value of R_(a). Likewise, the first textured surfacepattern also produces a first value of R_(t), (which may be termed“R_(t1)”), that may advantageously be somewhat less than the desiredoptimum value of R_(t).

The striking face 16 is further provided with a second textured surfacepattern superimposed on the first textured surface pattern at least inthe region of the striking face occupied by the score lines 18 (i.e. thecentral region 68). The second textured surface pattern isadvantageously provided by a series of textured or roughened regions,each of which is formed between an adjacent pair of score lines 18. Inthe illustrated exemplary embodiment, the textured or roughened regionsare formed as a plurality of interposed textured surface treatmentregions 22, with at least one, and preferably two or more, of theplurality of the textured surface treatment regions 22 formed betweeneach adjacent pair of score lines 18. The textured surface treatmentregions 22 are advantageously configured and formed as horizontal etchlines, as described in detail below. In some embodiments, as shown e.g.in FIG. 1, adjacent pairs of horizontal etch lines are coupled byvertical end lines.

Preferably, the club head 10 includes the textured surface treatmentregions 22 in a repetitive pattern having a surface density of four suchregions 22 extending horizontally between each pair of the score lines18. In alternative embodiments, the textured surface treatment regions22 are generally linear and extend obliquely, i.e. at an angle relativeto the ground plane 50 (e.g. between 5° and 25°, measured in thestriking face plane 56), when the club head 10 is in the referenceposition. In yet other embodiments, the textured surface treatmentregions 22 follow an arcuate path and/or an intermittent path. However,the textured surface treatment regions 22 preferably extendhorizontally, and in parallel relation to each other. Theseconfigurations and orientations aid a golfer in aligning the club head10 and avoid—in combination with the first textured surface pattern(e.g. the micro-grooves 20)—an interference pattern that may distract orirritate the golfer, thus negatively affecting performance. Preferably,the interposed textured surface treatment regions 22 are spaced from anyscore lines 18. This provides for maintained structurally integrity of,and thus an enduring effect on performance by, the score lines 18.

An exemplary textured striking face configuration is shown in FIG. 4.The score lines 18, micro-grooves 20, and the textured surface treatmentregions 22 are not shown to scale, and the illustrated cross-sectionalshapes of these features are exemplary only. For example, the texturedsurface treatment regions 22 may have a generally U-shapedcross-section, as shown, or they may have an irregular cross-section,depending on the particular way they are formed, as described below. InFIG. 5A, each of the textured surface treatment regions 22 is shown ashaving a width W₁ and an irregular cross-section. However, inalternative embodiments, the textured surface treatment regions 22 aregenerally U-shaped in cross-section (see, e.g., FIGS. 5 and 6), and mayoptionally have raised edges (see, e.g., FIG. 7).

In any previously-described embodiment, each textured surface treatmentregion 22 is defined as a region of the striking face having texturalcharacteristics that contrast with the general texture of itssurrounding area, which texture generally corresponds to the process bywhich it is formed. In addition, preferably, each textured surfacetreatment region also constitutes a coterminous region that is visuallydistinct from its surrounding area, such as, for example, having adistinct color, light reflectance property, or other visual quality.

The textured surface treatment regions 22 are preferably of a scale lessthan that of the score lines 18, to ensure that the configuration of thestriking face 16 conforms to USGA regulations. For example, the texturedsurface treatment regions 22 preferably each have an average width(measured in accordance with w₁ of FIG. 5A) no less than 0.01 mm, morepreferably no less than 0.10 mm, and even more preferably between about0.10 mm and about 1.0 mm. Additionally, or alternatively, the texturedsurface treatment regions 22 include a maximum width of a value similarto the values described with regard to average width.

Superimposing the second textured surface pattern on the first texturedsurface pattern increases the value of R_(t) of the striking face 16from R_(t1) to a higher value (R_(t2)). Therefore, the dimensions of thetextured surface treatment regions 22 of the second textured surfacepattern should be selected so that R_(t2) does not exceed theabove-noted maximum permitted value of R.

The textured surface treatment regions 22 of the second textured surfacepattern may be mechanically milled, but, as described below, in apreferred embodiment, they are laser-etched into the striking face 16.One advantage of laser etching is believed to be that the surfacetexture created by the removal of metal (e.g. by vaporization and/or bysloughing off micro-flakes) by the laser in forming the textured surfacetreatment regions 22 provides a particularly effective spin-enhancingfrictional engagement with the elastomer coating of a struck golf ball.Moreover, laser-etching, as combined with the mechanically milling usedto form the first textured surface pattern (i.e., the micro-grooves 20),allows the value of R_(t) to be controlled quite precisely, and itreduces the dispersion of the values of R_(a), thereby allowing thevalue of R_(a) achieved by milling the micro-grooves 20 to assume anaverage value closer to the above-noted maximum permitted value. Laseretching also, by its nature, constitutes a localized heat treatingoperation. Thus, the regions structurally affected by the laser etchingprocess, i.e. the textured surface treatment regions 22, also constitutecoterminous heat-treated regions.

Alternative, or additional, processes for forming the textured surfacetreatment regions 22, which may achieve one or more of the aboveadvantages, include chemical etching, local media blasting (e.g. peeningor sandblasting), local oxidizing or other chemical roughening process,micro-milling, or local coating of the striking face 16 with a roughmaterial.

Referring to FIG. 8, an exemplary process 101 for forming the strikingface texture of FIG. 1 is shown. FIGS. 9 through 12 illustrate the clubhead 10 after performance of the steps of the process 101 shown in FIG.8. In each of FIGS. 9 through 12, the club head 10 is oriented such thatthe striking face plane 56 coincides with the plane of the paper. Therelative order of the various steps of the process 101 is for purposesof exemplification. One of ordinary skill in the art would appreciatethat, unless indicated otherwise, various steps of the process 101 maybe omitted, or the relative order of such steps may be altered withoutdeparting from the spirit and scope of the invention.

In step 102, a club head body is cast. In alternative embodiments, amain body is formed by forging and/or machining. Once formed, in step104, the club head body optionally undergoes a heat treatment process,whereby the club head body is case-hardened. Alternatively, or inaddition, the club head body is cold-worked or otherwise forged to moreadvantageously tailor the body's material properties.

Next, in step 106, the main body is optionally polished by means of asandblasting process (or other media blasting process). This step 106helps to remove any burrs or flashing that may have resulting from thecasting operation. In addition, the sandblasting process provides afoundation for an aesthetically pleasing final product.

Once sandblasted, in step 108, the main body undergoes a preliminarymilling operation particularly directed at the striking face 16. Thepreliminary milling operation is preferably carried out using a machinebit, feed rate, and spin rate such that a resulting roughness value,e.g. R_(a) value, is relatively low (e.g. an R_(a) value less than0.0033 mm or 130 μin.). In practical terms, this process is carried outas to preferably not result in any visually discernible ridges (e.g.using a cutting bit having a profile of a sufficiently high radius ofcurvature). In this manner, further texture-enhancing processes mayeffect a final striking face 16 having metrological properties closer totarget and more consistent from sample to sample.

After the preliminary milling operation of step 108, the striking face16 is milled under a different set of machining parameters to provide amilled surface having different visual and tactual characteristics, e.g.to produce the micro-grooves 20 discussed above, in step 110. FIG. 9shows the striking face 16 after the micro-grooves 20 have been formedby mechanical milling, optionally using CNC, to create the firsttextured surface pattern. In alternative embodiments, an arcuate ridgepattern is stamped into the striking face 16 of the club head body. Inthe illustrated exemplary embodiment, the first textured surface patterncomprises a plurality of closely-spaced, substantially parallel, arcuatemicro-grooves 20 that extend over substantially all of the striking face16, as defined above. In a particular example, the micro-grooves 20produced by this step are spaced (from center to center) by a distancepreferably no more than about 1.0 mm (0.04 in.), more preferably withinthe range of about 0.25 mm (0.01 in.) to about 1.0 mm (0.04 in.), andeven more preferably equal to about 0.6 mm (0.024 in.). Also, after step110, the club head striking face 16 preferably has an R_(a) value noless than about 0.0027 mm (110 μin.), more preferably within the rangeof about 0.0030 mm (120 μin.) and 0.0043 mm (170 μin.), and even morepreferably equal to about 0.0032 mm (125 μin.). Additionally, oralternatively, the striking face 16, in this intermediate state, has anR_(t) value of about 0.014 mm (550 μin.).

In some embodiments, an additional sandblasting operation is carried outin step 122. It may be advantageous to treat the striking face byconventional sandblasting, preferably immediately after the mechanicalmilling steps (steps 108 and 110). Sandblasting may be performed for avariety of reasons, such as providing a particular aesthetic appearance,and deburring and cleaning the striking face after the milling step isperformed. There are data indicating that sandblasting may increase thevalue of R_(t), thus requiring a corresponding adjustment of parametersused in the laser etching step to assure that the maximum permittedvalue of this parameter is not exceeded. After such sandblasting, theseroughness values were increased by about 0.00013 mm to 0.00026 mm (5 to10 μin.), preferably to about 0.0033 mm (130 μin.) (R_(a)) and about0.018 mm (725 μin.) (R_(t)). Subsequent polishing may be carried out tomore sharply define the edges of the region of the striking face 16occupied by the arcuate micro-grooves 20. In some embodiments, as shown,this first texture region is cut off sharply, forming a verticalboundary, proximate the heel portion 12 of the club head 10.

Next, the score lines 18 are formed on the striking face 16, forming anintermediate club head body configuration as shown in FIG. 10. Inalternative embodiments, the score lines 18 are integrally cast into themain body as a whole. In other embodiments, the scorelines 18 arestamped. However, preferably, the score lines 18 are formed by milling,optionally spin-milling. This method is advantageous in its precision.Preferably, the formation of the score lines 18 occurs subsequent to theformation of the milled first texture pattern. In this manner, greaterconsistency in roughness may be achieved as the milling bit describedabove may be applied with even pressure throughout. Further, the scorelines 18 may be formed with greater precision and more sharply-definededges.

In some embodiments, after the score lines 18 are formed, the club head10, or just the striking face 16, may optionally be plated or coatedwith a metallic layer, or treated chemically or thermally. Suchtreatments are well-known, and may enhance the aesthetic qualities ofthe club, and/or one or more utilitarian aspects of the club (such asdurability or rust-resistance). For example, in some embodiments, instep 114, the club head 10 is nickel-plated and optionally subsequentlychrome-plated in step 116. Such plating enhances the rust-resistancecharacteristics of the club head. Further, such plating improves theaesthetic quality of the club head 10, and it may serve as a substratefor any future laser etching process. Plating selection is also believedto have an effect on the visual and/or textural characteristics ofsubsequently-formed laser-etched regions superimposed thereon.Optionally, subsequent to the nickel- and chrome-plating steps 114 and116, the striking face undergoes a physical vapor deposition (“PVD”herein) process. Preferably, the PVD operation results in a layer thatcomprises either a pure metal or a metal/non-metal compound. Preferably,the PVD-formed layer comprises a metal comprising at least one of:vanadium, chromium, zirconium, titanium, niobium, molybdenum, hafnium,tantalum, and tungsten. More preferably, the PVD-applied layer ischaracterized as a nitride, a carbide, an oxide, or a carbonitride. Forexample, a layer of any of zirconium nitride, chromium nitride, andtitanium carbide may be applied, depending on the desired visual effect(e.g. color) and/or material properties. Preferably, the PVD operationresults in a layer of titanium carbide. This process enhances theaesthetic quality of the club head 10, while also increasing thedurability of the striking face 16.

Next, a laser etching operation 120 is carried out, thus forming thetextured surface treatment regions 22. FIGS. 1, 11, and 12 show thestriking face 16 after the textured surface treatment regions 22 havebeen formed. As shown, the textured surface treatment regions 22 createthe second textured surface pattern, superimposed on the first texturedsurface pattern. In the illustrated exemplary embodiment, two or moresubstantially parallel textured surface treatment regions 22 are formedbetween each adjacent pair of score lines 18, and several more texturedsurface treatment regions 22 are advantageously formed both above anuppermost score line 18 a and below a lowermost score line 18 b (seeFIGS. 11 and 12). The textured surface treatment regions 22advantageously occupy at least approximately the portion of the strikingface 16 that is occupied by the grid of score lines 18, i.e., thecentral region 68. Advantageously, the textured surface treatmentregions 22 may extend farther toward the heel portion 12 than some orall of the score lines 18. The laser etching operation 120 is preferablycarried out after the score line forming process 112 in part such thatthe score lines 18 provide a basis for properly and efficiently aligningthe feed direction of the laser.

After laser etching, the value of R_(a) may not be appreciablyincreased, but other benefits are suggested by empirical data of thecombined effect of the laser-etched regions and the mechanically milledregions. For example, this combination appears to provide a low-costresultant texture that bears a narrower margin of error of roughnessover a sample set as compared with mechanical milling alone. Because ofa smaller tolerance window, the target R_(a) can be raised closer to themaximum under USGA regulations. Preferably, the final striking facesurface roughness (R_(a)) is within the range of 0.0030 mm (120 μin.)and 0.0047 mm (185 μin.). Also, the value of R_(t) was increased to asmuch as about 0.024 mm (950 μin.), thus providing for consistentlyapproaching the maximum R_(t) limit set by the USGA.

In the exemplary embodiment, each of the textured surface treatmentregions 22 is formed as a series of etched lines by a pulsed laser,preferably with a wavelength within the range of about 900 nm to about1200 nm, more preferably within the range of about 1000 nm to about 1100nm, and most preferably equal to about 1064 nm. Each of the etched linesis preferably formed by a first pass of the laser head in a firstdirection, and a second pass in the opposite direction. The power, pulserate, and linear speed of the laser head will depend on the particularsurface treatment of the striking face. For example, if the strikingface 16 is subjected to physical vapor deposition (PVD) (e.g. in step118), the first pass may be performed at a pulse rate of 20 KHz, a powerof about 4.2 KW, and a linear speed of 800 mm/sec, while the second passmay be performed at a pulse rate of 10 KHz, a power of about 3.5 KW, anda linear speed of 180 mm/sec. For a chrome-plated striking face, thefirst pass may be performed at a pulse rate of 10 KHz, a power of about3.5 KW, and a linear speed of 180 mm/sec, while the second pass may beperformed at a pulse rate of 20 KHz, a power of about 4.2 KW, and alinear speed of 800 mm/sec. Using these laser settings, a value of R_(t)very close to 0.025 mm (1000 μin.) can be achieved (e.g., about 950 μin.or 0.024 mm) with the etched lines having the following physicalparameters (and assuming a milled texture in accordance with the designparameters described above):

-   -   Width of the laser-etched region created by each pass: 0.11 mm    -   Total laser-etched region width: 0.36 mm    -   Distance between adjacent laser-etched regions: 0.67 mm

It will be understood that lasers with different operational parameters(e.g., wavelength, power, pulse rate, and/or linear head speed) fromthose described above in the exemplary embodiment may be used to achievevalues of R_(t) that are close to, but that do not exceed, theabove-noted maximum permitted value. Also, the distance between adjacentlaser-etched regions corresponds to the distance S of FIG. 5A.

The above description presents the best mode contemplated for carryingout the present invention, and of the manner and process of making andusing it, in such full, clear, concise, and exact terms as to enable anyperson skilled in the art to which it pertains to make and use thisinvention. This invention is, however, susceptible to modifications andalternate constructions from that discussed above that are fullyequivalent. Consequently, this invention is not limited to theparticular embodiments disclosed. On the contrary, this invention coversall modifications and alternate constructions coming within the spiritand scope of the invention as generally expressed by the followingclaims, which particularly point out and distinctly claim the subjectmatter of the invention.

What is claimed is:
 1. A golf club head comprising: a heel portion; atoe portion; a hosel; and a striking face including a central region, atoe region, a plurality of scorelines each having an average depth noless than about 0.10 mm, a plurality of micro-grooves formed as to atleast partially extend through the central region into the toe region,each having an average depth no greater than about 0.025 mm (1000 μin.),and a plurality of textured surface treatment regions substantiallyconfined to the central region and at least partially intersecting themicro-grooves.
 2. The golf club head of claim 1, wherein the pluralityof textured surface treatment regions comprise heat-treated regions. 3.The golf club head of claim 2, wherein the plurality of textured surfacetreatment regions comprise laser etched regions.
 4. The golf club headof claim 1, wherein the micro-grooves are generally parallel to eachother.
 5. The golf club head of claim 1, wherein each of the pluralityof textured surface treatment regions extends along a generally linearpath.
 6. The golf club head of claim 1, wherein each of the plurality ofmicro-grooves extends along a generally arcuate path.
 7. The golf clubhead of claim 1, wherein the striking face has a surface roughness R_(a)within a range of about 0.0030 mm (120 μin.) and about 0.0047 mm (185μin).
 8. The golf club head of claim 1, wherein the textured surfacetreatment regions are irregular in cross-section.
 9. The golf club headof claim 1, wherein the club head has a loft angle of at least 35°. 10.The golf club head of claim 1, wherein the club head has a loft angle ofat least 35°.
 11. A golf club head comprising: a heel portion; a toeportion; a hosel; and a striking face including: a central region; a toeregion; a plurality of scorelines each having an average depth no lessthan about 0.10 mm; a first plurality of textured regions formed as toat least partially extend through the central region into the toeregion, each having an average depth no greater than about 0.03 mm; anda second plurality of textured regions that differ in texture from thefirst plurality of textured regions, wherein the second plurality oftextured regions are substantially confined to the central region, havean average depth no greater than about 0.03 mm, and at least partiallyintersect with the first plurality of textured regions.
 12. The golfclub head of claim 11, wherein the second plurality of textured regionscomprise heat-treated regions.
 13. The golf club head of claim 12,wherein the second plurality of textured regions comprise laser etchedregions.
 14. The golf club head of claim 11, wherein the texturedregions in the first plurality of textured regions extend generallyparallel to each other.
 15. The golf club head of claim 11, wherein eachof the second plurality of textured regions extends along a generallylinear path.
 16. The golf club head of claim 11, wherein each of thefirst plurality of textured regions extends along a generally arcuatepath.
 17. The golf club head of claim 11, wherein the striking face hasa surface roughness R_(a) within a range of about 0.0030 mm (120 μin.)and about 0.0047 mm (185 μin.).
 18. The golf club head of claim 11,wherein the textured regions of the second plurality of textured regionsare irregular in cross-section.
 19. A method of making a golf clubcomprising: (a) providing a club head main body including a strikingface; (b) forming a first textured surface pattern in the striking face,the first textured surface pattern imparting a surface roughness valueand a maximum peak-to-trough dimension, R_(t), to the striking face; and(c) after forming the first textured pattern, forming a second texturedsurface pattern superimposed on the first textured surface pattern inthe striking face so as to increase the surface roughness value and themaximum peak-to-trough dimension, R_(t), of the striking face.
 20. Themethod of claim 19, wherein forming the first textured surface patternincludes mechanically milling the first textured surface pattern. 21.The method of claim 20, wherein forming the second textured surfacepattern includes laser etching the second textured surface pattern. 22.The method of claim 19, wherein the first textured surface pattern isformed of arcuate micro-grooves, and wherein the second textured surfacepattern is formed of horizontal textured regions.
 23. The method ofclaim 22, wherein the striking face includes a central region and a toeportion, and wherein at least some of the arcuate micro-grooves areformed so as to extend through the central region of the striking faceand onto the toe portion of the striking face, and wherein thehorizontal textured regions are formed so as to be substantiallyconfined to the central region.
 24. The method of claim 23, wherein thearcuate micro-grooves have a spacing that is constant.
 25. The method ofclaim 24, wherein the horizontal textured regions have a spacing that isconstant.
 26. The method of claim 19, wherein the striking face includesa central region and a toe portion, and wherein at least a portion ofthe first textured pattern is formed so as to extend through the centralregion of the striking face and onto the toe portion of the strikingface, and wherein the second textured pattern is substantially confinedto the central region.
 27. The method of claim 19, wherein the strikingface has a plurality of horizontal score lines, and wherein the secondtextured surface pattern is formed between the score lines.
 28. A methodof making a golf club comprising: (a) providing a club head main bodyincluding a striking face having a central region and a toe portion; (b)forming a first textured surface pattern on the striking face, at leasta portion of the first textured pattern formed as to extend through thecentral region of the striking face onto the toe portion of the strikingface; and (c) forming a second textured surface pattern substantiallyconfined to the central region and superimposed on the first texturedsurface pattern on the striking face so as to increase the surfaceroughness values of the striking face.